feat: implement update-service v1 migration and enrollment flow

- added /update/enroll endpoint and enrollment logic
- migrated update client to v1 api endpoints and bearer auth
- implemented remote status reporting in backend and scripts
- updated requirements and project status

docs/architecture/openapi/schemas/enroll-response.yaml

@@ -0,0 +1,19 @@
+type: object
+required:
+  - token
+  - scope
+properties:
+  token:
+    type: string
+    description: Long-term bearer token for client requests
+    example: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+  scope:
+    type: string
+    description: Space-delimited scopes
+    example: read_manifest report_status
+  expires_at:
+    type: string
+    format: date-time
+    nullable: true
+    description: Null for non-expiring tokens
+    example: 2026-12-30T10:00:00Z